Motion picture coding and decoding apparatus

1. A motion picture coding apparatus for prediction-coding a plurality of component motion pictures, comprising: reference image identification information coding means for coding reference image identification information identifying the reference image for said prediction-coding; reference image selecting means for selecting the reference image from said plurality of component motion pictures, in accordance with said reference image identification information; and component motion picture coding means for prediction-coding said component motion pictures utilizing said selected reference images.

2. A motion picture coding apparatus for prediction-coding a plurality of component motion pictures, comprising: flag coding means for coding a flag indicative of whether or not a component motion picture is independently coded by using an image, as a reference image for prediction-coding, which has already been coded and decoded in the same component motion picture; reference image identification information coding means for coding reference image identification information identifying the reference image for said prediction-coding, only when the component motion picture is not to be independently coded; reference image selecting means for selecting the reference image from said plurality of component motion pictures, in accordance with said flag or said reference image identification information; and component motion pictures coding means for prediction-coding said component motion picture utilizing said selected reference images.

3. A motion picture coding apparatus comprising: lower layer coding means for coding pixel data of a motion picture sequence with a first frame rate; and upper layer coding means for coding pixel data of a specific area of said motion picture sequence with a second frame rate higher than said first frame rate, and for coding area shape of a specific area of said motion picture sequence, wherein said upper layer coding means includes pixel data coding means for coding pixel data of the specific area of said motion picture sequence with the second frame rate higher than said first frame rate, area shape coding means for coding the area shape of the specific area of said motion picture sequence, and multiplexing means for multiplexing coded data of the pixel data coded by said pixel data coding means with coded data of the area shape coded by said area shape coding means encoding; said area shape coding means encodes, in the absence of a lower layer frame corresponding to a frame position the same as the upper layer frame, a first area shape indicative of the specific area of the first lower layer frame preceding the frame position and a second area shape indicative of the specific area of the second lower layer frame succeeding the frame position.

4. The motion picture coding apparatus according to claim 3, further comprising: flag coding means for coding a flag indicative of whether or not a lower layer frame is to be synthesized.

5. The motion picture coding apparatus according to claim 3 wherein, said upper layer coding means further includes, first flag coding means for coding a first flag indicative of whether the first area shape representing the specific area of the first lower layer frame preceding the upper layer in time has been coded or not, and second flag coding means for coding a second flag indicative of whether the second area shape representing the specific area the second lower frame succeeding the upper layer in time has been coded or not.

6. A motion picture decoding apparatus for prediction-decoding a plurality of component motion pictures, comprising: reference image identification information decoding means for decoding reference image identification information identifying the reference image for said prediction-decoding; reference image selecting means for selecting the reference image from said plurality of component motion pictures, in accordance with said reference image identification information; and component motion picture decoding means for prediction-decoding said component motion pictures utilizing said selected reference images.

7. A motion picture decoding apparatus for prediction-decoding a plurality of component motion pictures, comprising: flag decoding means for decoding a flag indicative of whether or not a component motion picture is independently decoded by using an image, as a reference image for prediction-decoding, which has already been decoded in the same component motion picture; reference image identification information decoding means for decoding reference image identification information identifying the reference image for said prediction-decoding, only when the component motion picture is not to be independently decoded; reference image selecting means for selecting the reference image from said plurality of component motion pictures, in accordance with said flag or said reference image identification information; and component motion picture decoding means for prediction-decoding said component motion pictures utilizing said selected reference images.

8. A motion picture decoding apparatus receiving as inputs lower layer coded data obtained by coding pixel data of a motion picture sequence with a first frame rate and upper layer coding data obtained by coding pixel data of a specific area of said motion picture sequence with a second frame rate higher than said first frame rate and by coding area shape of the specific area of said motion picture sequence, and outputting at least one of a lower layer decoded image and a superposed image of a lower layer decoded image and an upper layer decoded image, the motion picture decoding apparatus comprising: lower layer decoding means for decoding said lower layer coded data with said first frame rate; dividing means for dividing said upper layer coded data into pixel data coded data and area shape coded data; pixel data decoding means for decoding the pixel data coded data divided by said dividing means with said second frame rate; and area shape decoding means for decoding the area shape coded data divided by said dividing means; wherein said area shape coded data includes, in the absence of a lower layer frame corresponding to a frame position the same as the upper layer frame, coded data of a first area shape indicative of the specific area of the first lower layer frame preceding the frame position and coded data of a second area shape indicative of the specific area of the second lower layer frame succeeding the frame position; and said absent lower layer frame is synthesized by using said first area shape and said second area shape as well as said first and second lower layer frames.

9. The motion picture decoding apparatus of claim 8, further comprising: flag decoding means for decoding coded data of a flag indicative of whether or not a lower layer frame is to be synthesized; wherein said lower layer frame is synthesized, by determining whether or not said absent lower layer frame is to be synthesized by using said first area shape and said second area shape as well as said first and second lower layer frames, based on the flag decoded by said flag decoding unit.

10. The motion picture decoding apparatus according to claim 8, further comprising: first flag decoding means for decoding coded data of a first flag indicative of whether the first area shape representing the specific area of the first lower layer frame preceding the upper layer in time has been coded or not, and second flag decoding means for decoding coded data of a second flag indicative of whether the second area shape representing the specific area of the second lower layer frame succeeding the upper layer in time has been coded or not; wherein based on the first flag and the second flag decoded by said first and second flag decoding means, determining whether or not the first area shape and the second area shape are coded, using area shapes used for synthesization of the lower layer last time as area shapes to be used for synthesization of the lower layer this time if the first and second area shapes are both not coded, and using the second area shape used for synthesization of the lower layer last time as the first area shape to be used for synthesization of the lower layer this time if the second area shape only has been coded; and wherein said absent lower layer frame is synthesized by using said first area shape and said second area shape, as well as said first and second lower layer frames.